The Obama administration is set to unveil new procedures that will greatly expand the government’s ability to verify the income of Americans who seek government subsidies under the federal health care law.

“We’re going to be sampling 100 percent. There’s new information,” Gary Cohen, deputy director of the Centers for Medicare and Medicaid Services, told the House Ways and Means Committee on Thursday.

He made his assurances after Chairman Dave Camp, Michigan Republican, aired concerns that enrollees in state health exchanges will self-certify their income. The administration would have to cross-check that information much later, when the enrollees file their tax returns.

Mr. Cohen said the government will verify the income of everyone who applies for subsides on the state-based exchanges, where those without employer-based insurance can shop for private health coverage with the help of premium tax credits.

Daniel Werfel, acting director of the IRS, said the tax credits will be delivered through the health exchanges, and not directly to the individual enrollees.

In opening remarks, Mr. Camp said Americans face increasing uncertainty and confusion about the Affordable Care Act with roughly 60 days to go until the state-based insurance markets begin enrollment for coverage that takes effect in January.

He cited government accountability reports that suggest the federal government is lagging in its efforts to set up exchanges in more than half the states, and the White House’s decision July 2 to delay by one year, to 2015, the employer mandate requiring firms with 50 or more full-time workers to offer health insurance or pay fines.

Health and Human Services Secretary Kathleen Sebelius, he said, told the committee a few months ago “that the Obama administration ‘was on track to meet the October 1 deadline’ for the new health care law,” he said. “However, over the past two months, the evidence show just the opposite is true.”

On Friday, the House is scheduled to vote on a bill that would prevent the IRS from implementing and enforcing the health care law, a reaction to mounting distrust of the agency in the wake of a political targeting scandal in its tax-exempt organizations branch.

“At no time is the tax data to be displayed to anyone outside of the marketplace itself,” Mr. Werfel said Thursday in opening remarks.

Michigan Rep. Sander Levin, the ranking Democrat on the Ways and Means panel, said the hearing had been convened “under the pretense that House Republicans are interested in learning about the implementation of the landmark law.”

“The Republican mission is clear: Don’t implement, destroy,” he said.

“How else,” he added, “can they explain why they have leaned on outside organizations, including the National Football League, to discourage them from helping to educate Americans about current law health insurance opportunities and assistance that will be available through the marketplaces?”